Industrial plating systems utilize a series of tanks into which parts to be plated are sequentially dipped. These tanks contain cleaners, etching solutions, plating preparations, plating solutions, and finishing solutions. For optimum plating results, the parts must be thoroughly rinsed between certain of the solution treatments. This rinsing also prevents the contamination of one solution tank by the residue solution carried by the part from a previous solution tank. Since the plating solutions may be very expensive, the latter function of the rinsing process is as important as the former.
A water rinse comprising pure water is often used between certain solution treatments. In order to maintain the purity of the water, it is common to have fresh water continually entering the bottom of a rinse tank with an overflow trough used to skim excess sludge and contaminants from the top of the tank. The impurities from the rinse tank must be treated and neutralized before being discharged into a sewer system. This is usually accomplished by continually measuring the PH in the discharge flow and adding a base or an acid as may be appropriate to effect neutralization.
The above-described process is not entirely satisfactory. The continual running of pure water into the rinse tanks results in a tremendous amount of water being used daily in order to keep the system operative. Further, the addition of a neutralizer to the discharge flow on a continual basis as required by the PH level in the discharge flow does not satisfactorily neutralize the discharge since the PH levels may change rapidly.